Light-emitting device having a phosphor particle layer with specific thickness

Abstract

A light emitting device having a die that includes a light source that generates light of a first wavelength and a layer of phosphor particles covering the die is disclosed. The phosphor particles convert a portion of the light of the first wavelength to light of a second wavelength. The light source can be fabricated by attaching the light source to a substrate, and converting the light source by applying a light converting layer that includes a volatile carrier material and particles of a phosphor that convert light of the first wavelength to light of the second wavelength over the light source. The volatile carrier material is then caused to evaporate leaving a layer of the phosphor particles over the light source. A binder material can be incorporated in the volatile carrier for binding the phosphor particles to one another after the volatile carrier material is evaporated.

1. A light emitting device comprising:
 a light source that generates light of a first wavelength, said light source comprising a die that emits light at said first wavelength; 
 a conformal layer of phosphor particles covering said die and in direct contact therewith, said phosphor particles converting at least a portion of said light of said first wavelength to light of a second wavelength, said layer having a substantially uniform thickness of less than 100 μm over said die; and 
 a reflecting cup comprising reflective sidewalls, said die being located in said cup such that a portion of said light generated by said die is reflected from said cup, said layer of phosphor particles covering a portion of said reflective sidewalls. 
 
     
     
       2. A light emitting device comprising:
 a light source that generates light of a first wavelength; and 
 a layer of phosphor particles covering said light source, said phosphor particles converting at least a portion of said light of said first wavelength to light of a second wavelength, said layer comprising a residue of a slurry of said phosphor particles in a volatile solvent, said residue comprising the portion of said slurry that remains when a portion of said volatile solvent is removed. 
 
     
     
       3. The light emitting device of  claim 2  wherein said light source comprises an LED. 
     
     
       4. The light emitting device of  claim 2  further comprising a layer of clear material covering said layer of phosphor particles. 
     
     
       5. The light emitting device of  claim 4  wherein said clear material further comprises a diffusing material for scattering light generated by said light source and said phosphor particles. 
     
     
       6. The light emitting device of  claim 5  further comprising a layer of transparent bulk encapsulating material over said layer of clear material. 
     
     
       7. The light emitting device of  claim 2  further comprising a reflecting cup comprising reflective sidewalls, a die located in said cup such that a portion of said light generated by said die is reflected from said cup, said layer of phosphor particles covering a portion of said reflective sidewalls. 
     
     
       8. The light emitting device of  claim 2  further comprising a layer of clear material between said light source and said layer of phosphor particles.